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1.
Front Bioeng Biotechnol ; 11: 1261178, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37790258

RESUMEN

Nickel serves as an essential micronutrient for the human body, playing a vital role in various enzymatic processes. However, excessive nickel entering the environment can cause pollution and pose serious risks to animals, plants, and human health. High concentrations of nickel ions in the human body increase the risk of various diseases, highlighting the need for accurate measurement of nickel ions levels. In this study, we designed a sequence-specific cleavage probe for nickel (II) ion called SSC-Ni. Similar to the TaqMan probe, SSC-Ni is an off-on fluorescent probe with an exceptionally low background fluorescence signal. It exhibits high detection specificity, making it highly selective for nickel ions, and the detection limit of the probe towards Ni2+ is as low as 82 nM. The SSC-Ni probe can be utilized for convenient and cost-effective high-throughput quantitative detection of nickel ions in serum. Its user-friendly operation and affordability make it a practical solution. By addressing the lack of simple and effective nickel ion detection methods, this probe has the potential to contribute significantly to environmental monitoring and the protection of human health.

2.
Front Microbiol ; 14: 1269275, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38260899

RESUMEN

Background: There are many similarities in the clinical manifestations of human norovirus and SARS-CoV-2 infections, and nucleic acid detection is the gold standard for diagnosing both diseases. In order to expedite the identification of norovirus and SARS-CoV-2, a quantitative one-step triplex reverse transcription PCR (RT-qPCR) method was designed in this paper. Methods: A one-step triplex RT-qPCR assay was developed for simultaneous detection and differentiation of human norovirus GI (NoV-GI), GII (NoV-GII) and SARS-CoV-2 from fecal specimens. Results: The triplex RT-qPCR assay had high detection reproducibility (CV < 1%) and sensitivity. The lower limits of detection (LLOD95) of the triplex RT-qPCR assay for each target site were 128.5-172.8 copies/mL, and LLOD95 of the singleplex RT-qPCR assay were 110.3-142.0 copies/mL. Meanwhile, among the detection of clinical oropharyngeal swabs and fecal specimens, the results of the singleplex and triplex RT-qPCR assay showed high agreement. Conclusion: The triplex RT-qPCR assay for simultaneous detection of NoV-GI, NoV-GII and SARS-CoV-2 from fecal specimens has high clinical application value.

3.
Biosci Rep ; 2022 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-36205098

RESUMEN

PINK1, as the first reported ubiquitin kinase, can phosphorylate ubiquitin (Ub) at Ser65 site, which regulates the structure and function of Ub monomer. However, the levels of PINK1 and phosphorylated Ub (pUb) are very low in normal cells. Here we show that when proteasome activity is inhibited, the levels of soluble PINK1 (sPINK1) and pUb will increase significantly. Further we show that ubiquitin phosphorylation can inhibit the formation of K48-linked ubiquitin chains in vivo and in vitro, and the retracted state of pUb plays a leading role in the inhibition process. Ubiquitination is a necessary process for substrates degradation. Thus, phosphorylation can regulate proteasomal degradation of substrates.

4.
Proc Natl Acad Sci U S A ; 114(26): 6770-6775, 2017 06 27.
Artículo en Inglés | MEDLINE | ID: mdl-28611216

RESUMEN

Ubiquitin (Ub) is an important signaling protein. Recent studies have shown that Ub can be enzymatically phosphorylated at S65, and that the resulting pUb exhibits two conformational states-a relaxed state and a retracted state. However, crystallization efforts have yielded only the structure for the relaxed state, which was found similar to that of unmodified Ub. Here we present the solution structures of pUb in both states obtained through refinement against state-specific NMR restraints. We show that the retracted state differs from the relaxed state by the retraction of the last ß-strand and by the extension of the second α-helix. Further, we show that at 7.2, the pKa value for the phosphoryl group in the relaxed state is higher by 1.4 units than that in the retracted state. Consequently, pUb exists in equilibrium between protonated and deprotonated forms and between retracted and relaxed states, with protonated/relaxed species enriched at slightly acidic pH and deprotonated/retracted species enriched at slightly basic pH. The heterogeneity of pUb explains the inability of phosphomimetic mutants to fully mimic pUb. The pH-sensitive conformational switch is likely preserved for polyubiquitin, as single-molecule FRET data indicate that pH change leads to quaternary rearrangement of a phosphorylated K63-linked diubiquitin. Because cellular pH varies among compartments and changes upon pathophysiological insults, our finding suggests that pH and Ub phosphorylation confer additional target specificities and enable an additional layer of modulation for Ub signals.


Asunto(s)
Ubiquitina/química , Humanos , Concentración de Iones de Hidrógeno , Resonancia Magnética Nuclear Biomolecular , Fosforilación , Dominios Proteicos , Ubiquitina/genética , Ubiquitina/metabolismo
5.
Dalton Trans ; (29): 3528-33, 2006 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-16855754

RESUMEN

New selective Zn2+ fluorescent sensors, di(2-quinoline-carbaldehyde)-2,2'-bibenzoyl-hydrazone (QB1) and di(2-quinolinecarbaldehyde)-6,6'-dicarboxylic acid hydrazone-2,2'-bipyridine (QB2), have been designed and prepared. Both QB sensors exhibit an emission band centered at 405 nm (excitation at 350 nm) with low quantum yield. Zinc binding not only red-shifts the emission band to 500 nm, but also enhances the fluorescence intensity by an order of magnitude based on the deprotonization strategy via self-assembly. These probes are highly selective for Zn2+ over biologically relevant alkali metals, alkaline earth metals and the first row transition metals such as Mn2+, Fe2+, Co2+ and Ni2+ in buffered aqueous DMSO solution.

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